Sodium benzenesulphinate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Data is from peer reviewed journal

Justification for type of information:

Data is from peer reviewed journal

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)

Principles of method if other than guideline:

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance sodium benzenesulfinate. The study was performed according to OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test).

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material: sodium benzenesulfinate
- Molecular formula (if other than submission substance): C6H6O2S.Na
- Molecular weight (if other than submission substance): 164.16 g/mol
- Smiles notation (if other than submission substance): c1(ccccc1)S(=O)[O-].[Na+]
- InChI: 1S/C6H6O2S.Na/c7-9(8)6-4-2-1-3-5-6;/h1-5H,(H,7,8);/q;+1/p-1
- Substance type: Organic
- Physical state: Solid
- Other: Sodium benzene sulphinate was obtained from Aldrich Chemicals Ltd., Gillingham, Dorset, UK.

Oxygen conditions:

not specified

Inoculum or test system:

other: Sewage effluent, MITI or activated sludge was used as a test inoculum.

Details on inoculum:

- Concentration of sludge: 0.5 ml effluent /l or 30 mg activated sludge solids/l

Duration of test (contact time):

28 d

Initial conc.:

ca. 10 - < 50 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Test temperature: 20 or 25ᵒC

Key result

Parameter:

% degradation (DOC removal)

Value:

16

Sampling time:

28 d

Remarks on result:

other: when sewage effluent was used as a test inoculum.

Key result

Parameter:

% degradation (DOC removal)

Value:

98

Sampling time:

21 d

Remarks on result:

other: when MITI sludge was used as a test inoculum.

Key result

Parameter:

% degradation (DOC removal)

Value:

85

Sampling time:

28 d

Remarks on result:

other: when MITI sludge was used as a test inoculum.

Details on results:

Test chemical was not adequately removed in the 28-day period when the inoculum used was sewage effluent, whereas test chemical was removed to a much larger extent when activated sludge was used as the inoculum. Test substance undergoes 16, 98 and 85% degradation by using DOC removal parameter in 28 days by using sewage effluent, MITI and activated sludge as a test inoculum.

During the 28 days of the screening test, the original substance may be transformed sufficiently rapidly to their products, which are fairly readily biodegradable, to cause most of the DOC to disappear.

 

When activated sludge wasusedas an inoculum, the test substance sodium benzene sulphinate was removed to a much larger extent.

 

Table: Removal of Sodium Benzene Sulphinate (as DOC) in ISO Die-Away Tests

 

Inoculum	% Removal of DOC after (days)				Estimated time for removal of 70% (days)
Effluent (0.5 ml/l)	7	14	21	28
	0 0 5	6 20 21	11 - -	16 15 9	- - -
MITI Sludge        (30 mg/l)	0 0 0	20 80 18	102 93 76	98 94 94	8 5 10
Activated sludge       (30 mg/l)	5 5 0	32 47 13	- - 35	20 71 85	- 20 13

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

The percentage degradation of test substance was determined to be 16, 98 and 85% by using DOC removal parameter in 28 days by using sewage effluent, MITI and activated sludge as a test inoculum. Thus, based on percentage degradation, test substance sodium benzenesulfinate was considered to be readily biodegradable in water.

Executive summary:

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance sodium benzenesulfinate. The study was performed according to OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test).Sewage effluent, MITI or activated sludge was used as a test inoculum. Concentration of sludge used was 0.5 ml effluent /l or 30 mg activated sludge solids/l and initial test substance conc. used was 10-50 mg/l based on DOC. The study was performed at a temperature of 20 or 25ᵒC.Test chemical was not adequately removed in the 28-day period when the inoculum used was sewage effluent, whereas test chemical was removed to a much larger extent when activated sludge wasused as the inoculum. The percentage degradation of test substance was determined to be16, 98 and 85% by using DOC removal parameter in 28 days by using sewage effluent, MITI and activated sludge as a test inoculum. Thus, based on percentage degradation, test substance sodium benzenesulfinate was considered to be readily biodegradable in nature.

Description of key information

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance sodium benzenesulfinate (H A Painter and E F King, 1986). The study was performed according to OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test).Sewage effluent, MITI or activated sludge was used as a test inoculum. Concentration of sludge used was 0.5 ml effluent /l or 30 mg activated sludge solids/l and initial test substance conc. used was 10-50 mg/l based on DOC. The study was performed at a temperature of 20 or 25ᵒC.Test chemical was not adequately removed in the 28-day period when the inoculum used was sewage effluent, whereas test chemical was removed to a much larger extent when activated sludge wasusedas the inoculum. The percentage degradation of test substance was determined to be16, 98 and 85% by using DOC removal parameter in 28 days by using sewage effluent, MITI and activated sludge as a test inoculum. Thus, based on percentage degradation, test substance sodium benzenesulfinate was considered to be readily biodegradable in nature.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Various experimental and supporting studies for the target compoundsodium benzenesulfinate(CAS No. 873-55-2) were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental study from peer reviewed journal (H A Painter and E F King, 1986),biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of test substance sodium benzenesulfinate (CAS no. 873-55-2). The study was performed according to OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test).Sewage effluent, MITI or activated sludge was used as a test inoculum. Concentration of sludge used was 0.5 ml effluent /l or 30 mg activated sludge solids/l and initial test substance conc. used was 10-50 mg/l based on DOC. The study was performed at a temperature of 20 or 25ᵒC.Test chemical was not adequately removed in the 28-day period when the inoculum used was sewage effluent, whereas test chemical was removed to a much larger extent when activated sludge was used as the inoculum. The percentage degradation of test substance was determined to be16, 98 and 85% by using DOC removal parameter in 28 days by using sewage effluent, MITI and activated sludge as a test inoculum. Thus, based on percentage degradation, test substance sodium benzenesulfinate was considered to be readily biodegradable in nature.

 

In a supporting data, biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of test substance sodium benzenesulfinate (CAS no. 873-55-2) (H A Painter and E F King, 1986). The study was performed according to EEC Respirometric method.The screening methods which was employed include MITI & EEC respirometric method. Activated sludge was used as a test inoculum. Concentration of sludge used was 30 mg activated sludge solids/l and initial test substance conc. used was 100 mg/l based on test material. The study was performed at a temperature of 20 or 25ᵒC. In screening tests, 60% ThOD and 70% DOC removal was achieved in a ’10 -day window’. In screening tests, 60% ThOD and 70% DOC removal was achieved in a ’10-day window’. The percentage degradation of test substance was determined to be 70 and 100% by ThOD and DOC removal parameter after 28 days in EEC respirometric method, whereas 95 and 97% degradation of test substance was determined after 28 days in MITI respirometric method. Thus, based on percentage degradation, test substance sodium benzenesulfinate was considered to be readily biodegradable in nature.

 

Another supporting biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance sodium benzenesulfinate (CAS no. 873-55-2) under aerobic conditions at a temperature of 20°C (J. STRUIJS AND J. STOLTENKAMP, 1990). Activated Sludge was used as a test inoculum obtained from local sewage treatment plant (de Bilt, The Netherlands).The activated sludge was sampled the day before the incubations started and was aerated overnight. Stock solutions were prepared from twice distilled water. Concentration of inoculum i.e, sludge used was 3.9 mg/l and initial test substance conc. used in the study was 10 mg/l, respectively. Test and blank solutions were transferred to caliberated 120 ml serum bottles in a headspace/solution ratio ½. The serum bottles were sealed with three-part caps consisting of butyl rubber septa, pierceable, and closed aluminium screw tops. Incubations were carried out in the dark at 20°C on a rotary shaker (120 rpm). Weekly, part of the bottles were sacrificed for CO2 headspace analyses and if possible, DOC measurements of the solution.The CO2 concentrations in the headspace of the acidified solution were related to the corresponding blank from which the level of mineralization was calculated as percent ThCO2 (theoretical amount of carbon dioxide of the compound). The test was terminated when percent ThC02 exceeded 70%. For the blank control, a series containing a mineral solution with inoculum was prepared. Prior to the analyses of inorganic carbon, a stock solution was prepared from 44 1.7 mg anhydrous sodium carbonate in 1 liter CO*-free water, from which standard solutions of 0, 5, and 10 mg/liter DIC (dissolved inorganic carbon) were made. These standard solutions were transferred to duplicate 120-ml serum bottles in a 1/2 headspace/solution ratio. The bottles were sealed with the three-part caps. Bottles to be sacrificed for measurements and bottles containing the freshly prepared standard solutions were acidified by injection of 1 ml 7N H3P04 through the septum. To allow equilibration the serum bottles were shaken in the dark at 120 rpm for 1 hr. After equilibration headspace CO* analyses were performed as follows. Gas samples of 1000µ1 were taken through the septa and injected directly into the reaction chamber of the Dohrmann DC-80 carbon analyzer. Injection of the gas sample was carried out by piercing a Hamilton gas syringe 1 cm into the injection port and drawing the gas smoothly into the reaction vessel. The concentrations of inorganic carbon produced in the test and in the blank were obtained from the calibration line of the standard solutions. Before gas analyses proper functioning of the carbon analyzer was checked with a 10 mg/liter DOC sodium biphthalate standard solution.DOC measurements of the soluble test compounds were carried out with a Technicon AA” auto-analyzer on Day 0 and after each carbon dioxide analysis. Samples were centrifuged at 5000g before DOC was measured. The percentage degradation of test substance was determined to be 28 – 35% degradation by ThCO2 parameter in 28 days. Thus, based on percentage degradation, test substance sodium benzenesulfinate was considered to be inherently biodegradable in nature.

 

In a supporting study from authoritative database (J-CHECK, 2017), biodegradation screening test was conducted for 21 days for evaluating the percentage biodegradability of the test substance sodium benzenesulfinate (CAS no. 873-55-2). Concentration of inoculum i.e, sludge used was 100 mg/l and initial test substance conc. used in the study was 30 mg/l, respectively. The percentage degradation of test substance was determined to be 99, 81 and 67% by BOD, TOC and UV-Vis parameter in 21 days. Thus, based on percentage degradation, test substance sodium benzenesulfinate was considered to be readily biodegradable in nature.

 

For the target chemical sodium benzenesulfinate (CAS no. 873-55-2), biodegradation study was conducted for 30 days for evaluating the percentage biodegradability of test substance sodium benzenesulfinate (J. Struijs and R. Van Den Berg, 1995). The study was performed according to OECD Guideline. Test inoculum activated sludge was obtained from communal waste water treatment plant. The percentage degradation of test substance was determined to be 100% degradation in 30 days. Thus, based on percentage degradation, test substance sodium benzenesulfinate was considered to be readily biodegradable in nature.

 

Although 1 study from peer reviewed journal (J. STRUIJS AND J. STOLTENKAMP, 1990) indicate that the chemical is inherently biodegradable in nature, based on the overall reported results for target chemical sodium benzenesulfinate (from peer reviewed journal and authoritative database J-CHECK), it can be concluded that the test substance sodium benzenesulfinate can be expected to be readily biodegradable in nature.